The present disclosure is directed to a method and apparatus for controlling a vehicle HVAC system, and more particularly to a method and apparatus for controlling a front and rear integrated vehicle HVAC system so as to prevent an inverse air flow from being output from an undesired vent outlet and/or blower intake.
To improve the operation of vehicle heating, ventilation and air conditioning (HVAC) systems, independent climate control region functionality has been developed and implemented. Vehicle cabins may generally be conceptually divided into a front region and a rear region, and further divided into a driver's side region and a passenger's side region. As used herein, the front region corresponds to an area where a driver and front passenger seat are located, and the rear region corresponds to a vehicle cabin area where rear seats are provided. According to the independent climate control functionality, custom climate control can be provided for passengers seated in any of the plurality of vehicle cabin regions.
To efficiently control climate throughout both the front and rear regions of the vehicle cabin, a front and rear integrated HVAC system may be employed. Such a system may utilize one or more blower units associated with each vehicle cabin region generating a climate controlling air flow to be expelled through one or more vent outlets or ducts into the corresponding vehicle cabin region. Additionally, the front and rear integrated HVAC system may employ other climate controlling mechanisms or components for the front and rear portions of the vehicle, such as evaporators, heater cores, etc. Furthermore, custom controls for each of the various regions within a vehicle cabin are provided such that climate control for each of the regions can be particularly adjusted to suit the comfort of passengers disposed in those regions.
Though such custom controls have been developed to allow for customized climate control in each of the various vehicle cabin regions, and each of the regions may have dedicated HVAC components, the HVAC system remains a single, integrated system. As such, especially in situations where one blower is operating at a relatively higher rate than others (e.g. has a higher voltage applied thereto than another blower), pressure differentials within the integrated HVAC system may exist. Such pressure differentials may result in an inadvertent redirecting of air flow, as vacuum attraction toward lower pressure regions within the HVAC system may not agree with the intended air flow path. This may result in air flow originating from a blower associated with a particular vehicle cabin region being expelled through a vent outlet associated with a different vehicle cabin region and/or an air intake of another blower.
This problem may be further exacerbated by the fact that the air flow being expelled from the unintended vent outlet may not be climate controlled in the manner desired by the passengers in the subject region, or at all. For example, if the HVAC system is operating in a heating mode, it is possible that unheated air flow may be passing through an unintended vent outlet, thereby expelling cold air into a vehicle cabin region where heated air is desired. This degrades the operation of the customizable climate control for the various vehicle cabin regions.